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Hi Henry

I measure the delta between Point Wild and Cape Belsham, both on Elephant 
Island, to be 1.5 arcminutes (90 arc seconds) in arc (longitude, not time).  
This is based upon the modern chart 29104

http://data.aad.gov.au/aadc/mapcat/display_map.cfm?map_id=5823

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Worsley's definition of the latitude and longitude of Cape Belsham is directly 
in front of us.  On 24 April 1916, he indicates that the distance made good 
to noon on 25 April 1916 is NORTH 64 miles.  He carefully records his 
latitude on 25 April as South 60 degrees 0 minutes and his longitude as West 
54 degrees 50 minutes.  His latitude on 24 April was 61 degrees 4 minutes.  
Hence we can deduce what he thought his longitude of Cape Belsham.

Worsley's Est of Cape Belsham   
                     South 61 deg 4 minutes    West 54 deg 50 min
Modern (Chart 29104) of same    
                     South 61 deg 6 min 22 sec West 54 deg 53 min 45 sec

Displacement between the two
                     3.43 kilometers (2.13 miles)

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What is terrifically interesting is that Worsley, on 24 April 1916, calculates 
the longitude at West 54 deg 19 min 45 sec.  His estimate of the longitude of 
Cape Belsham is West 54 deg 50 min.  Thus the delta is 30 min 15 sec.  By 
simple conversion formulas, this should be 2 minutes 1 second of time.

Yet he records 1 minute 4 seconds of time.  Perhaps he understands just how 
much trouble he is in when he states "No observation for latitude could be 
obtained.  Longitude of Cape Belsham is only opportunity of know it is, allow 
1 minute 4 second more  slow = 11 minute 55 second slow."

This is a 57 second error, using his own estimate of Cape Belsham.

When we inject the modern longitude of Cape Belsham, the error grows.

Best Regards
Brad



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